package com.huawei;

import java.util.Scanner;

/**
 * Created by Z-hong on 2024/7/4.
 */

public class HJ23 {
    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        int[] arr = new int[26];
        char [] chars=str.toCharArray();

        for (char c : chars) {
            arr[c-'a']++;
        }
        int count =30;
        for (int i = 0; i < arr.length; i++) {
            if (arr[i]!=0){
               count= Math.min(arr[i],count);
            }
        }
        StringBuffer sb=new StringBuffer();
        for (int i = 0; i < chars.length; i++) {
            if(arr[chars[i]-'a']!=count){
                sb.append(chars[i]);
            }
        }
        System.out.println(sb.toString());
    }
}
